At present, a Long Term Evolution (Long Term Evolution, hereinafter referred to as LTE) system has been widely applied in the communications field. In the LTE system, downlink data that is sent to user equipment (User Equipment, hereinafter referred to as UE) by a base station may include PDSCH data transmitted on a physical downlink shared channel (Physical Downlink Shared Channel, hereinafter referred to as PDSCH) and PDCCH control signaling transmitted on a physical downlink control channel (Physical Downlink Control Channel, hereinafter referred to as PDCCH). The PDCCH control signaling may include a scheduling command, a power control command, a measurement reporting command, and the like.
The foregoing downlink data sent by the base station may not be capable of being correctly received by the UE. If no acknowledgment information from the UE is received within a period of time after the base station sends the downlink data, the base station may retransmit the same downlink data.
If a signal, from the base station, received by the UE is relatively weak, the base station may need to retransmit the downlink data including the PDCCH control signaling and the PDSCH data to the UE for multiple times. Such a manner of repeatedly retransmitting downlink data usually causes an excessive long delay to downlink data transmission. If the repeatedly retransmitted downlink data is a scheduling command used to schedule uplink/downlink data, an excessive long delay may also be caused to transmission of the scheduled uplink/downlink data. If the repeatedly retransmitted downlink data is a power control command or a measurement reporting command, problems such as that power of the UE is not adjusted in time and that a measurement is not reported in time may also be caused.